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De Koninck BP, Brazeau D, Deshaies AA, Briand MM, Maschke C, Williams V, Arbour C, Williamson D, Duclos C, Bernard F, Blain-Moraes S, De Beaumont L. Modulation of brain activity in brain-injured patients with a disorder of consciousness in intensive care with repeated 10-Hz transcranial alternating current stimulation (tACS): a randomised controlled trial protocol. BMJ Open 2024; 14:e078281. [PMID: 38991682 PMCID: PMC11243138 DOI: 10.1136/bmjopen-2023-078281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/13/2024] Open
Abstract
INTRODUCTION Therapeutic interventions for disorders of consciousness lack consistency; evidence supports non-invasive brain stimulation, but few studies assess neuromodulation in acute-to-subacute brain-injured patients. This study aims to validate the feasibility and assess the effect of a multi-session transcranial alternating current stimulation (tACS) intervention in subacute brain-injured patients on recovery of consciousness, related brain oscillations and brain network dynamics. METHODS AND ANALYSES The study is comprised of two phases: a validation phase (n=12) and a randomised controlled trial (n=138). Both phases will be conducted in medically stable brain-injured adult patients (traumatic brain injury and hypoxic-ischaemic encephalopathy), with a Glasgow Coma Scale score ≤12 after continuous sedation withdrawal. Recruitment will occur at the intensive care unit of a Level 1 Trauma Centre in Montreal, Quebec, Canada. The intervention includes a 20 min 10 Hz tACS at 1 mA intensity or a sham session over parieto-occipital cortical sites, repeated over five consecutive days. The current's frequency targets alpha brain oscillations (8-13 Hz), known to be associated with consciousness. Resting-state electroencephalogram (EEG) will be recorded four times daily for five consecutive days: pre and post-intervention, at 60 and 120 min post-tACS. Two additional recordings will be included: 24 hours and 1-week post-protocol. Multimodal measures (blood samples, pupillometry, behavioural consciousness assessments (Coma Recovery Scale-revised), actigraphy measures) will be acquired from baseline up to 1 week after the stimulation. EEG signal analysis will focus on the alpha bandwidth (8-13 Hz) using spectral and functional network analyses. Phone assessments at 3, 6 and 12 months post-tACS, will measure long-term functional recovery, quality of life and caregivers' burden. ETHICS AND DISSEMINATION Ethical approval for this study has been granted by the Research Ethics Board of the CIUSSS du Nord-de-l'Île-de-Montréal (Project ID 2021-2279). The findings of this two-phase study will be submitted for publication in a peer-reviewed academic journal and submitted for presentation at conferences. The trial's results will be published on a public trial registry database (ClinicalTrials.gov). TRIAL REGISTRATION NUMBER NCT05833568.
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Affiliation(s)
- Béatrice P De Koninck
- Psychology, University of Montreal, Montreal, Quebec, Canada
- Research Center, Hopital du Sacre-Coeur de Montreal, Montreal, Quebec, Canada
| | - Daphnee Brazeau
- Psychology, University of Montreal, Montreal, Quebec, Canada
- Research Center, Hopital du Sacre-Coeur de Montreal, Montreal, Quebec, Canada
| | | | - Marie-Michele Briand
- CIUSSS du Nord-de-l'Ile-de-Montreal, Montreal, Quebec, Canada
- IRDPQ, Montreal, Quebec, Canada
| | - Charlotte Maschke
- McGill University, Montreal, Quebec, Canada
- Montreal General Hospital, Montreal, Quebec, Canada
| | - Virginie Williams
- Research Center, Hopital du Sacre-Coeur de Montreal, Montreal, Quebec, Canada
| | - Caroline Arbour
- Research Center, Hopital du Sacre-Coeur de Montreal, Montreal, Quebec, Canada
- University of Montreal, Montreal, Quebec, Canada
| | | | - Catherine Duclos
- Research Center, Hopital du Sacre-Coeur de Montreal, Montreal, Quebec, Canada
- Anesthesiology and Pain Medicine, University of Montreal, Montreal, Quebec, Canada
| | - Francis Bernard
- Research Center, Hopital du Sacre-Coeur de Montreal, Montreal, Quebec, Canada
- Medicine, University of Montreal, Montreal, Quebec, Canada
| | - Stefanie Blain-Moraes
- Montreal General Hospital, Montreal, Quebec, Canada
- Physical and Occupational Therapy, McGill University, Montreal, Quebec, Canada
| | - Louis De Beaumont
- Research Center, Hopital du Sacre-Coeur de Montreal, Montreal, Quebec, Canada
- Surgery, University of Montreal, Montreal, Quebec, Canada
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You Y, Li Y, Yu B, Ying A, Zhou H, Zuo G, Xu J. A study on EEG differences between active counting and focused breathing tasks for more sensitive detection of consciousness. Front Neurosci 2024; 18:1341986. [PMID: 38533445 PMCID: PMC10963484 DOI: 10.3389/fnins.2024.1341986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 02/26/2024] [Indexed: 03/28/2024] Open
Abstract
Introduction In studies on consciousness detection for patients with disorders of consciousness, difference comparison of EEG responses based on active and passive task modes is difficult to sensitively detect patients' consciousness, while a single potential analysis of EEG responses cannot comprehensively and accurately determine patients' consciousness status. Therefore, in this paper, we designed a new consciousness detection paradigm based on a multi-stage cognitive task that could induce a series of event-related potentials and ERD/ERS phenomena reflecting different consciousness contents. A simple and direct task of paying attention to breathing was designed, and a comprehensive evaluation of consciousness level was conducted using multi-feature joint analysis. Methods We recorded the EEG responses of 20 healthy subjects in three modes and reported the consciousness-related mean event-related potential amplitude, ERD/ERS phenomena, and the classification accuracy, sensitivity, and specificity of the EEG responses under different conditions. Results The results showed that the EEG responses of the subjects under different conditions were significantly different in the time domain and time-frequency domain. Compared with the passive mode, the amplitudes of the event-related potentials in the breathing mode were further reduced, and the theta-ERS and alpha-ERD phenomena in the frontal region were further weakened. The breathing mode showed greater distinguishability from the active mode in machine learning-based classification. Discussion By analyzing multiple features of EEG responses in different modes and stimuli, it is expected to achieve more sensitive and accurate consciousness detection. This study can provide a new idea for the design of consciousness detection methods.
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Affiliation(s)
- Yimeng You
- Cixi Biomedical Research Institute, Wenzhou Medical University, Ningbo, Zhejiang, China
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang, China
- Ningbo Cixi Institute of Biomedical Engineering, Ningbo, Zhejiang, China
| | - Yahui Li
- Cixi Biomedical Research Institute, Wenzhou Medical University, Ningbo, Zhejiang, China
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang, China
- Ningbo Cixi Institute of Biomedical Engineering, Ningbo, Zhejiang, China
| | - Baobao Yu
- Cixi Biomedical Research Institute, Wenzhou Medical University, Ningbo, Zhejiang, China
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang, China
- Ningbo Cixi Institute of Biomedical Engineering, Ningbo, Zhejiang, China
| | - Ankai Ying
- Cixi Biomedical Research Institute, Wenzhou Medical University, Ningbo, Zhejiang, China
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang, China
- Ningbo Cixi Institute of Biomedical Engineering, Ningbo, Zhejiang, China
| | - Huilin Zhou
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang, China
- Ningbo Cixi Institute of Biomedical Engineering, Ningbo, Zhejiang, China
| | - Guokun Zuo
- Cixi Biomedical Research Institute, Wenzhou Medical University, Ningbo, Zhejiang, China
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang, China
- Ningbo Cixi Institute of Biomedical Engineering, Ningbo, Zhejiang, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jialin Xu
- Cixi Biomedical Research Institute, Wenzhou Medical University, Ningbo, Zhejiang, China
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang, China
- Ningbo Cixi Institute of Biomedical Engineering, Ningbo, Zhejiang, China
- University of Chinese Academy of Sciences, Beijing, China
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Li J, Huang B, Wang F, Xie Q, Xu C, Huang H, Pan J. A Potential Prognosis Indicator Based on P300 Brain-Computer Interface for Patients with Disorder of Consciousness. Brain Sci 2022; 12:1556. [PMID: 36421880 PMCID: PMC9688541 DOI: 10.3390/brainsci12111556] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/30/2022] [Accepted: 11/11/2022] [Indexed: 08/08/2023] Open
Abstract
For patients with disorders of consciousness, such as unresponsive wakefulness syndrome (UWS) patients and minimally conscious state (MCS) patients, their long treatment cycle and high cost commonly put a heavy burden on the patient's family and society. Therefore, it is vital to accurately diagnose and predict consciousness recovery for such patients. In this paper, we explored the role of the P300 signal based on an audiovisual BCI in the classification and prognosis prediction of patients with disorders of consciousness. This experiment included 18 patients: 10 UWS patients and 8 MCS- patients. At the three-month follow-up, we defined patients with an improved prognosis (from UWS to MCS-, from UWS to MCS+, or from MCS- to MCS+) as "improved patients" and those who stayed in UWS/MCS as "not improved patients". First, we compared and analyzed different types of patients, and the results showed that the P300 detection accuracy rate of "improved" patients was significantly higher than that of "not improved" patients. Furthermore, the P300 detection accuracy of traumatic brain injury (TBI) patients was significantly higher than that of non-traumatic brain injury (NTBI, including acquired brain injury and cerebrovascular disease) patients. We also found that there was a positive linear correlation between P300 detection accuracy and CRS-R score, and patients with higher P300 detection accuracy were likely to achieve higher CRS-R scores. In addition, we found that the patients with higher P300 detection accuracies tend to have better prognosis in this audiovisual BCI. These findings indicate that the detection accuracy of P300 is significantly correlated with the level of consciousness, etiology, and prognosis of patients. P300 can be used to represent the preservation level of consciousness in clinical neurophysiology and predict the possibility of recovery in patients with disorders of consciousness.
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Affiliation(s)
- Jingcong Li
- School of Software, South China Normal University, Guangzhou 510631, China
- Pazhou Lab, Guangzhou 510631, China
| | - Biao Huang
- School of Software, South China Normal University, Guangzhou 510631, China
| | - Fei Wang
- School of Software, South China Normal University, Guangzhou 510631, China
- Pazhou Lab, Guangzhou 510631, China
| | - Qiuyou Xie
- Joint Research Centre for Disorders of Consciousness, Department of Rehabilitation Medicine, Zhujiang Hospital of Southern Medical University, Guangzhou 510631, China
| | - Chengwei Xu
- Joint Research Centre for Disorders of Consciousness, Department of Rehabilitation Medicine, Zhujiang Hospital of Southern Medical University, Guangzhou 510631, China
| | - Haiyun Huang
- School of Software, South China Normal University, Guangzhou 510631, China
- Pazhou Lab, Guangzhou 510631, China
| | - Jiahui Pan
- School of Software, South China Normal University, Guangzhou 510631, China
- Pazhou Lab, Guangzhou 510631, China
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Tivadar RI, Knight RT, Tzovara A. Automatic Sensory Predictions: A Review of Predictive Mechanisms in the Brain and Their Link to Conscious Processing. Front Hum Neurosci 2021; 15:702520. [PMID: 34489663 PMCID: PMC8416526 DOI: 10.3389/fnhum.2021.702520] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 07/12/2021] [Indexed: 01/22/2023] Open
Abstract
The human brain has the astonishing capacity of integrating streams of sensory information from the environment and forming predictions about future events in an automatic way. Despite being initially developed for visual processing, the bulk of predictive coding research has subsequently focused on auditory processing, with the famous mismatch negativity signal as possibly the most studied signature of a surprise or prediction error (PE) signal. Auditory PEs are present during various consciousness states. Intriguingly, their presence and characteristics have been linked with residual levels of consciousness and return of awareness. In this review we first give an overview of the neural substrates of predictive processes in the auditory modality and their relation to consciousness. Then, we focus on different states of consciousness - wakefulness, sleep, anesthesia, coma, meditation, and hypnosis - and on what mysteries predictive processing has been able to disclose about brain functioning in such states. We review studies investigating how the neural signatures of auditory predictions are modulated by states of reduced or lacking consciousness. As a future outlook, we propose the combination of electrophysiological and computational techniques that will allow investigation of which facets of sensory predictive processes are maintained when consciousness fades away.
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Affiliation(s)
| | - Robert T. Knight
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
- Department of Psychology, University of California, Berkeley, Berkeley, CA, United States
| | - Athina Tzovara
- Institute of Computer Science, University of Bern, Bern, Switzerland
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
- Sleep-Wake Epilepsy Center | NeuroTec, Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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Mulkey M, Everhart DE, Gencarelli A, Sorrell A, Kim S. A Review of Neuronal Pathways Associated With Consciousness. J Neurosci Nurs 2021; 53:39-43. [PMID: 33252410 PMCID: PMC8127025 DOI: 10.1097/jnn.0000000000000559] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
ABSTRACT INTRODUCTION: Accurate communication of information regarding fluctuations in level of consciousness is critical. It is, important for nurses to understand terms related to consciousness to appropriately assess and implement plans of care. CONTENT: Although the neurobiology of consciousness is complex and multifaceted, consciousness can be conceptualized as having 2 distinct but interrelated dimensions: arousal and awareness. The different levels of consciousness are thought to fall on a continuum ranging from being fully awake to coma. CONCLUSION: This article focuses on the terms of consciousness, awareness, and arousal along with nursing implications where appropriate.
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Salvato G, Berlingeri M, De Maio G, Curto F, Chieregato A, Magnani FG, Sberna M, Rosanova M, Paulesu E, Bottini G. Autonomic responses to emotional linguistic stimuli and amplitude of low-frequency fluctuations predict outcome after severe brain injury. NEUROIMAGE-CLINICAL 2020; 28:102356. [PMID: 32750635 PMCID: PMC7397392 DOI: 10.1016/j.nicl.2020.102356] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 06/26/2020] [Accepted: 07/18/2020] [Indexed: 01/22/2023]
Abstract
Acute DOC patients with favourable outcome show preserved event-related electrodermal response. Acute DOC patients showed reduced fALFF in the posterior cingulate cortex. Event-related electrodermal activity correlated with the fALFFs in the PCC in the acute phase.
An accurate prognosis on the outcome of brain-injured patients with disorders of consciousness (DOC) remains a significant challenge, especially in the acute stage. In this study, we applied a multiple-technique approach to provide accurate predictions on functional outcome after 6 months in 15 acute DOC patients. Electrophysiological correlates of implicit cognitive processing of verbal stimuli and data-driven voxel-wise resting-state fMRI signals, such as the fractional amplitude of low-frequency fluctuations (fALFF), were employed. Event-related electrodermal activity, an index of autonomic activation, was recorded in response to emotional words and pseudo-words at baseline (T0). On the same day, patients also underwent a resting-state fMRI scan. Six months later (T1), patients were classified as outcome-negative and outcome-positive using a standard functional outcome scale. We then revisited the baseline measures to test their predictive power for the functional outcome measured at T1. We found that only outcome-positive patients had an earlier, higher autonomic response for words compared to pseudo-words, a pattern similar to that of healthy awake controls. Furthermore, DOC patients showed reduced fALFF in the posterior cingulate cortex (PCC), a brain region that contributes to autonomic regulation and awareness. The event-related electrodermal marker of residual cognitive functioning was found to have a significant correlation with residual local neuronal activity in the PCC. We propose that a residual autonomic response to cognitively salient stimuli, together with a preserved resting-state activity in the PCC, can provide a useful prognostic index in acute DOC.
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Affiliation(s)
- Gerardo Salvato
- Cognitive Neuropsychology Centre, ASST "Grande Ospedale Metropolitano" Niguarda, Milano, Italy; Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy; NeuroMi, Milan Center for Neuroscience, Milano, Italy.
| | - Manuela Berlingeri
- NeuroMi, Milan Center for Neuroscience, Milano, Italy; Department of Humanistic Studies, University of Urbino Carlo Bo, Urbino, Italy; Center of Developmental Neuropsychology, Area Vasta 1, ASUR Marche, Pesaro, Italy.
| | - Gabriele De Maio
- Cognitive Neuropsychology Centre, ASST "Grande Ospedale Metropolitano" Niguarda, Milano, Italy
| | - Francesco Curto
- Department of Neuroresuscitation and Intensive Care, ASST "Grande Ospedale Metropolitano" Niguarda, Milano, Italy
| | - Arturo Chieregato
- Department of Neuroresuscitation and Intensive Care, ASST "Grande Ospedale Metropolitano" Niguarda, Milano, Italy
| | - Francesca Giulia Magnani
- Cognitive Neuropsychology Centre, ASST "Grande Ospedale Metropolitano" Niguarda, Milano, Italy; Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy; NeuroMi, Milan Center for Neuroscience, Milano, Italy
| | - Maurizio Sberna
- Department of Neuroradiology, ASST "Grande Ospedale Metropolitano" Niguarda, Milano, Italy
| | - Mario Rosanova
- Department of Biomedical and Clinical Sciences "Luigi Sacco", University of Milano, Italy; Fondazione Europea di Ricerca Biomedica, FERB Onlus, Milano, Italy
| | - Eraldo Paulesu
- Psychology Department and NeuroMI-Milan Center for Neuroscience, University of Milano-Bicocca, Milan, Italy; fMRI Unit, I.R.C.C.S. Galeazzi, Milano, Italy
| | - Gabriella Bottini
- Cognitive Neuropsychology Centre, ASST "Grande Ospedale Metropolitano" Niguarda, Milano, Italy; Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy; NeuroMi, Milan Center for Neuroscience, Milano, Italy
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Anestis DM, Tsitsopoulos PP, Tsonidis CA, Foroglou N. The current significance of the FOUR score: A systematic review and critical analysis of the literature. J Neurol Sci 2019; 409:116600. [PMID: 31811988 DOI: 10.1016/j.jns.2019.116600] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 11/04/2019] [Accepted: 11/26/2019] [Indexed: 10/25/2022]
Abstract
BACKGROUND The Full Outline of Un-Responsiveness Score (FOURs) is a scale for clinical assessment of consciousness that was introduced to overcome disadvantages of the widely accepted Glasgow Coma Scale (GCS). OBJECTIVE To carry out a systematic review and critical analysis of the available literature on the clinical application of FOURs and perform a comparison to GCS, in terms of reliability and predictive value. METHODS Initial search retrieved a total of 147 papers. After applying strict inclusion criteria and further article selection to overcome data heterogeneity, a statistical comparison of inter-rater reliability, in-hospital mortality and long-term outcome prediction between the two scales in the adult and pediatric population was done. RESULTS Even though FOURs is more complicated than GCS, its application remains quite simple. Its reliability, validity and predictive value have been supported by an increasing number of studies, especially in critical care. A statistically significant difference (p = .034) in predicting in-hospital mortality in adults, in favor of FOURs when compared to GCS, was found. However, whether it poses a clinically significant advantage in detecting patients' deterioration and outcome prediction, compared to other scaling systems, remains unclear. CONCLUSIONS Further studies are needed to discern the FOURs' clinical usefulness, especially in patients in non-critical condition, with milder disorders of consciousness.
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Affiliation(s)
- Dimitrios M Anestis
- Department of Neurosurgery, Hippokration General Hospital, Aristotle University School of Health Sciences, Faculty of Medicine, Thessaloniki, Greece.
| | - Parmenion P Tsitsopoulos
- Department of Neurosurgery, Hippokration General Hospital, Aristotle University School of Health Sciences, Faculty of Medicine, Thessaloniki, Greece
| | - Christos A Tsonidis
- Department of Neurosurgery, Hippokration General Hospital, Aristotle University School of Health Sciences, Faculty of Medicine, Thessaloniki, Greece
| | - Nikolaos Foroglou
- Department of Neurosurgery, AHEPA University Hospital, Aristotle University School of Health Sciences, Faculty of Medicine, Thessaloniki, Greece
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Wang F, He Y, Qu J, Cao Y, Liu Y, Li F, Yu Z, Yu R, Li Y. A Brain-Computer Interface Based on Three-Dimensional Stereo Stimuli for Assisting Clinical Object Recognition Assessment in Patients With Disorders of Consciousness. IEEE Trans Neural Syst Rehabil Eng 2019; 27:507-513. [PMID: 30714927 DOI: 10.1109/tnsre.2019.2896092] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The coma recovery scale-revised (CRS-R) behavioral scale is commonly used for the clinical evaluation of patients with disorders of consciousness (DOC). However, since DOC patients generally cannot supply stable and efficient behavioral responses to external stimulation, evaluation results based on behavioral scales are not sufficiently accurate. In this paper, we proposed a novel brain-computer interface (BCI) based on 3D stereo audiovisual stimuli to supplement object recognition evaluation in the CRS-R. During the experiment, subjects needed to follow the instructions and to focus on the target object on the screen, whereas EEG data were recorded and analyzed in real time to determine the object of focus, and the detection result was output as feedback. Thirteen DOC patients participated in the object recognition assessments using the 3D audiovisual BCI and CRS-R. None of the patients showed object recognition function in the CRS-R assessment before the BCI experiment. However, six of these DOC patients achieved accuracies that were significantly higher than the chance level in the BCI-based assessment, indicating the successful detection of object recognition function in these six patients using our 3D audiovisual BCI system. These results suggest that the BCI method may provide a more sensitive object recognition evaluation compared with CRS-R and may be used to assist clinical CRS-R for DOC patients.
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Straudi S, Bonsangue V, Mele S, Craighero L, Montis A, Fregni F, Lavezzi S, Basaglia N. Bilateral M1 anodal transcranial direct current stimulation in post traumatic chronic minimally conscious state: a pilot EEG-tDCS study. Brain Inj 2019; 33:490-495. [PMID: 30632807 DOI: 10.1080/02699052.2019.1565894] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
OBJECTIVE We tested the preliminary effects of bilateral anodal transcranial direct current stimulation (tDCS) in patients with disorders of consciousness. DESIGN Open label pilot study. SUBJECTS Ten chronic (greater than 12 months) patients in a minimally conscious state (MCS) following severe traumatic brain injury. METHODS The patients received 10 sessions of bilateral M1 anodal tDCS. Behavioural changes were assessed with the Coma Recovery Scale-Revised (CRS-R) before stimulation (T-1, T0), after five sessions (T1), at the end of the stimulation (T2), after two weeks (T3) and after three months (T4). Moreover, an EEG assessment was conducted. RESULTS Eight out of 10 patients showed new clinical signs of consciousness; specifically, a 2-point CRS-R improvement was detected in the last follow-up (p = 0.004). EEG upper α bandwidth was greater in the parietal site at T1 (p < 0.034). In addition, we found a significant correlation between behavioral and EEG indices at T1 (r = 0.89; p = 0.001). CONCLUSION This preliminary study presents several limitations (small sample size and no control group). However, it provides important initial data that can be used to design randomized clinical trials testing this novel approach in MCS and to further explore EEG as a neural marker for the effects of tDCS.
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Affiliation(s)
- Sofia Straudi
- a Neuroscience and Rehabilitation Department , Ferrara University Hospital , Ferrara , Italy
| | - Valentina Bonsangue
- a Neuroscience and Rehabilitation Department , Ferrara University Hospital , Ferrara , Italy
| | - Sonia Mele
- b Biomedical and Specialty Surgical Sciences Department , Ferrara University , Ferrara , Italy
| | - Laila Craighero
- b Biomedical and Specialty Surgical Sciences Department , Ferrara University , Ferrara , Italy
| | - Andrea Montis
- c Sardinian Health Trust , Neurorehabilitation Unit, San Martino Hospital , Oristano , Italy
| | - Felipe Fregni
- d Department of Physical Medicine and Rehabilitation, Harvard Medical School , Neuromodulation Center, Spaulding Rehabilitation Hospital , Boston , MA , USA
| | - Susanna Lavezzi
- a Neuroscience and Rehabilitation Department , Ferrara University Hospital , Ferrara , Italy
| | - Nino Basaglia
- a Neuroscience and Rehabilitation Department , Ferrara University Hospital , Ferrara , Italy
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Xie Q, Pan J, Chen Y, He Y, Ni X, Zhang J, Wang F, Li Y, Yu R. A gaze-independent audiovisual brain-computer Interface for detecting awareness of patients with disorders of consciousness. BMC Neurol 2018; 18:144. [PMID: 30296948 PMCID: PMC6176505 DOI: 10.1186/s12883-018-1144-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 08/29/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Currently, it is challenging to detect the awareness of patients who suffer disorders of consciousness (DOC). Brain-computer interfaces (BCIs), which do not depend on the behavioral response of patients, may serve for detecting the awareness in patients with DOC. However, we must develop effective BCIs for these patients because their ability to use BCIs does not as good as healthy users. METHODS Because patients with DOC generally do not exhibit eye movements, a gaze-independent audiovisual BCI is put forward in the study where semantically congruent and incongruent audiovisual number stimuli were sequentially presented to evoke event-related potentials (ERPs). Subjects were required to pay attention to congruent audiovisual stimuli (target) and ignore the incongruent audiovisual stimuli (non-target). The BCI system was evaluated by analyzing online and offline data from 10 healthy subjects followed by being applied to online awareness detection in 8 patients with DOC. RESULTS According to the results on healthy subjects, the audiovisual BCI system outperformed the corresponding auditory-only and visual-only systems. Multiple ERP components, including the P300, N400 and late positive complex (LPC), were observed using the audiovisual system, strengthening different brain responses to target stimuli and non-target stimuli. The results revealed the abilities of three of eight patients to follow commands and recognize numbers. CONCLUSIONS This gaze-independent audiovisual BCI system represents a useful auxiliary bedside tool to detect the awareness of patients with DOC.
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Affiliation(s)
- Qiuyou Xie
- Coma Research Group, Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, 510010 China
| | - Jiahui Pan
- School of Software, South China Normal University, Guangzhou, 510641 China
- Center for Brain Computer Interfaces and Brain Information Processing, South China University of Technology, Guangzhou, 510640 China
| | - Yan Chen
- Coma Research Group, Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, 510010 China
| | - Yanbin He
- Coma Research Group, Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, 510010 China
| | - Xiaoxiao Ni
- Coma Research Group, Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, 510010 China
| | - Jiechun Zhang
- Coma Research Group, Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, 510010 China
| | - Fei Wang
- Center for Brain Computer Interfaces and Brain Information Processing, South China University of Technology, Guangzhou, 510640 China
| | - Yuanqing Li
- Center for Brain Computer Interfaces and Brain Information Processing, South China University of Technology, Guangzhou, 510640 China
| | - Ronghao Yu
- Coma Research Group, Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, 510010 China
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Kempny AM, James L, Yelden K, Duport S, Farmer SF, Diane Playford E, Leff AP. Patients with a severe prolonged Disorder of Consciousness can show classical EEG responses to their own name compared with others' names. Neuroimage Clin 2018; 19:311-319. [PMID: 30013914 PMCID: PMC6044184 DOI: 10.1016/j.nicl.2018.04.027] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 04/05/2018] [Accepted: 04/22/2018] [Indexed: 01/26/2023]
Abstract
Patients in Vegetative State (VS), also known as Unresponsive Wakefulness State (UWS) are deemed to be unaware of themselves or their environment. This is different from patients diagnosed with Minimally Conscious state (MCS), who can have intermittent awareness. In both states, there is a severe impairment of consciousness; these disorders are referred to as disorders of consciousness (DOC) and if the state is prolonged, pDOC. There is growing evidence that some patients who are behaviourally in VS/UWS can show neural activation to environmental stimuli and that this response can be detected using functional brain imaging (fMRI/PET) and electroencephalography (EEG). Recently, it has also been suggested that a more reliable detection of brain responsiveness and hence a more reliable differentiation between VS/UWS and MCS requires person-centred and person-specific stimuli, such as the subject's own name stimulus. In this study we obtained event related potential data (ERP) from 12 healthy subjects and 16 patients in pDOC, five of whom were in the VS/UWS and 11 in the Minimally Conscious State (MCS). We used as the ERP stimuli the subjects' own name, others' names and reversed other names. We performed a sensor level analysis using Statistical Parametric Mapping (SPM) software. Using this paradigm in 4 DOC patients (3 in MCS, and 1 in VS/UWS) we detected a statistically significant difference in EEG response to their own name versus other peoples' names with ERP latencies (~300 ms and ~700 ms post stimuli). Some of these differences were similar to those found in a control group of healthy subjects. This study shows the feasibility of using self-relevant stimuli such as a subject's own name for assessment of brain function in pDOC patients. This neurophysiological test is suitable for bed-side/hospital based assessment of pDOC patients. As it does not require sophisticated scanning equipment it can feasibly be used within a hospital or care setting to help professionals tailor medical and psycho-social management for patients.
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Affiliation(s)
- Agnieszka M Kempny
- The Institute of Neuro-palliative Rehabilitation, Royal Hospital for Neuro-disability, London SW15 3SW, UK; Department of Brain Repair and Rehabilitation, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK.
| | - Leon James
- The Institute of Neuro-palliative Rehabilitation, Royal Hospital for Neuro-disability, London SW15 3SW, UK
| | - Kudret Yelden
- The Institute of Neuro-palliative Rehabilitation, Royal Hospital for Neuro-disability, London SW15 3SW, UK; Department of Brain Repair and Rehabilitation, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | - Sophie Duport
- The Institute of Neuro-palliative Rehabilitation, Royal Hospital for Neuro-disability, London SW15 3SW, UK
| | - Simon F Farmer
- The National Hospital for Neurology & Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - E Diane Playford
- The Institute of Neuro-palliative Rehabilitation, Royal Hospital for Neuro-disability, London SW15 3SW, UK; Health Sciences, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
| | - Alexander P Leff
- Department of Brain Repair and Rehabilitation, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK; Institute of Cognitive Neuroscience, University College London, Queen Square, WC1N 3AR London, UK
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12
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Wang F, He Y, Qu J, Xie Q, Lin Q, Ni X, Chen Y, Pan J, Laureys S, Yu R, Li Y. Enhancing clinical communication assessments using an audiovisual BCI for patients with disorders of consciousness. J Neural Eng 2017; 14:046024. [DOI: 10.1088/1741-2552/aa6c31] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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13
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Li Y, Pan J, He Y, Wang F, Laureys S, Xie Q, Yu R. Detecting number processing and mental calculation in patients with disorders of consciousness using a hybrid brain-computer interface system. BMC Neurol 2015; 15:259. [PMID: 26670376 PMCID: PMC4681180 DOI: 10.1186/s12883-015-0521-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Accepted: 12/11/2015] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND For patients with disorders of consciousness such as coma, a vegetative state or a minimally conscious state, one challenge is to detect and assess the residual cognitive functions in their brains. Number processing and mental calculation are important brain functions but are difficult to detect in patients with disorders of consciousness using motor response-based clinical assessment scales such as the Coma Recovery Scale-Revised due to the patients' motor impairments and inability to provide sufficient motor responses for number- and calculation-based communication. METHODS In this study, we presented a hybrid brain-computer interface that combines P300 and steady state visual evoked potentials to detect number processing and mental calculation in Han Chinese patients with disorders of consciousness. Eleven patients with disorders of consciousness who were in a vegetative state (n = 6) or in a minimally conscious state (n = 3) or who emerged from a minimally conscious state (n = 2) participated in the brain-computer interface-based experiment. During the experiment, the patients with disorders of consciousness were instructed to perform three tasks, i.e., number recognition, number comparison, and mental calculation, including addition and subtraction. In each experimental trial, an arithmetic problem was first presented. Next, two number buttons, only one of which was the correct answer to the problem, flickered at different frequencies to evoke steady state visual evoked potentials, while the frames of the two buttons flashed in a random order to evoke P300 potentials. The patients needed to focus on the target number button (the correct answer). Finally, the brain-computer interface system detected P300 and steady state visual evoked potentials to determine the button to which the patients attended, further presenting the results as feedback. RESULTS Two of the six patients who were in a vegetative state, one of the three patients who were in a minimally conscious state, and the two patients that emerged from a minimally conscious state achieved accuracies significantly greater than the chance level. Furthermore, P300 potentials and steady state visual evoked potentials were observed in the electroencephalography signals from the five patients. CONCLUSIONS Number processing and arithmetic abilities as well as command following were demonstrated in the five patients. Furthermore, our results suggested that through brain-computer interface systems, many cognitive experiments may be conducted in patients with disorders of consciousness, although they cannot provide sufficient behavioral responses.
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Affiliation(s)
- Yuanqing Li
- Center for Brain Computer Interfaces and Brain Information Processing, South China University of Technology, Guangzhou, 510640, China.
- Guangzhou Key Laboratory of Brain Computer Interaction and Applications, Guangzhou, China.
| | - Jiahui Pan
- School of Software, South China Normal University, Guangzhou, 510641, China
| | - Yanbin He
- Guangzhou Key Laboratory of Brain Computer Interaction and Applications, Guangzhou, China
- Coma Research Group, Centre for Hyperbaric Oxygen and Neurorehabilitation, General Hospital of Guangzhou Military Command of People's Liberation Army, Guangzhou, 510010, China
| | - Fei Wang
- Center for Brain Computer Interfaces and Brain Information Processing, South China University of Technology, Guangzhou, 510640, China
- Guangzhou Key Laboratory of Brain Computer Interaction and Applications, Guangzhou, China
| | - Steven Laureys
- Coma Science Group, Cyclotron Research Centre and Neurology Department, University and University Hospital of Liège, 4000, Liège, Belgium
| | - Qiuyou Xie
- Guangzhou Key Laboratory of Brain Computer Interaction and Applications, Guangzhou, China
- Coma Research Group, Centre for Hyperbaric Oxygen and Neurorehabilitation, General Hospital of Guangzhou Military Command of People's Liberation Army, Guangzhou, 510010, China
| | - Ronghao Yu
- Guangzhou Key Laboratory of Brain Computer Interaction and Applications, Guangzhou, China.
- Coma Research Group, Centre for Hyperbaric Oxygen and Neurorehabilitation, General Hospital of Guangzhou Military Command of People's Liberation Army, Guangzhou, 510010, China.
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14
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Kirschner A, Cruse D, Chennu S, Owen AM, Hampshire A. A P300-based cognitive assessment battery. Brain Behav 2015; 5:e00336. [PMID: 26085962 PMCID: PMC4467771 DOI: 10.1002/brb3.336] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 02/15/2015] [Accepted: 02/25/2015] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND It is well established that some patients who are diagnosed as being in a vegetative state or a minimally conscious state show reliable signs of volition that may only be detected by measuring neural responses. A pertinent question is whether these patients are capable of higher cognitive processes. METHODS Here, we develop a series of EEG paradigms that probe several core aspects of cognition at the bedside without the need for motor responses and explore the sensitivity of this approach in a group of healthy controls. RESULTS Using analysis of ERPs alone, this method can determine with high reliability whether individual participants are able to attend a stimulus stream, maintain items in working memory, or solve complex grammatical reasoning problems. CONCLUSION We suggest that this approach could form the basis of a brain-based battery for assessing higher cognition in patients with severe motor impairments or disorders of consciousness.
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Affiliation(s)
- Aaron Kirschner
- The Brain and Mind Institute, University of Western OntarioLondon, Ontario, Canada
| | - Damian Cruse
- The Brain and Mind Institute, University of Western OntarioLondon, Ontario, Canada
| | - Srivas Chennu
- Department of Clinical Neurosciences, The University of CambridgeCambridge, UK
| | - Adrian M Owen
- The Brain and Mind Institute, University of Western OntarioLondon, Ontario, Canada
| | - Adam Hampshire
- The Computational, Cognitive and Clinical Neuroimaging Laboratory, Division of Brain Sciences, Imperial College LondonLondon, UK
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Thonnard M, Gosseries O, Demertzi A, Lugo Z, Vanhaudenhuyse A, Bruno MA, Chatelle C, Thibaut A, Charland-Verville V, Habbal D, Schnakers C, Laureys S. Effect of zolpidem in chronic disorders of consciousness: a prospective open-label study. FUNCTIONAL NEUROLOGY 2014; 28:259-64. [PMID: 24598393 DOI: 10.11138/fneur/2013.28.4.259] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Zolpidem has been reported as an "awakening drug" in some patients with disorders of consciousness (DOC). We here present the results of a prospective openlabel study in chronic DOC patients. Sixty patients (35±15 years; 18 females; mean time since insult ± SD: 4±5.5 years; 31 with traumatic etiology) with a diagnosis of vegetative state/unresponsive wakefulness syndrome (n=28) or minimally conscious state (n=32) were behaviorally assessed using the Coma Recovery Scale-Revised (CRS-R) before and one hour after administration of 10 mg of zolpidem. At the group level, the diagnosis did not change after intake of zolpidem (p=0.10) and CRS-R total scores decreased (p=0.01). Twelve patients (20%) showed improved behaviors and/or CRS-R total scores after zolpidem administration but in only one patient was the diagnosis after zolpidem intake found to show a significant improvement (functional object use), which suggested a change of diagnosis. However, in this patient, a double-blind placebo-controlled trial was performed in order to better specify the effects of zolpidem, but the patient, on this trial, failed to show any clinical improvements. The present open-label study therefore failed to show any clinically significant improvement (i.e., change of Effect of zolpidem in chronic disorders of consciousness: a prospective open-label study diagnosis) in any of the 60 studied chronic DOC patients.
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16
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Demertzi A, Jox RJ, Racine E, Laureys S. A European survey on attitudes towards pain and end-of-life issues in locked-in syndrome. Brain Inj 2014; 28:1209-15. [PMID: 24911332 DOI: 10.3109/02699052.2014.920526] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVES Patients with locked-in syndrome often self-report a higher quality of life than generally expected. This study reports third-person attitudes towards several salient issues on locked-in syndrome. METHODS Close-ended survey among conference attendees from 33 European countries. Analysis included chi-square tests and logistic regressions. RESULTS From the 3332 respondents (33% physicians, 18% other clinicians, 49% other professions; 47% religious), 90% agreed that patients with locked-in syndrome can feel pain. The majority (75%) disagreed with treatment withdrawal, but 56% did not wish to be kept alive if they imagined themselves in this condition (p < 0.001). Religious and southern Europeans opposed to treatment withdrawal more often than non-religious (p < 0.001) and participants from the North (p = 0.001). When the locked-in syndrome was compared to disorders of consciousness, more respondents endorsed that being in a chronic locked-in syndrome was worse than being in a vegetative state or minimally conscious state for patients (59%) than they thought for families (40%, p < 0.001). CONCLUSIONS Personal characteristics mediate opinions about locked-in syndrome. The dissociation between personal preferences and general opinions underlie the difference in perspective in disability. Ethical responses to dilemmas involving patients with locked-in syndrome should consider the diverging ethical attitudes of stakeholders.
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Affiliation(s)
- Athena Demertzi
- Coma Science Group, Cyclotron Research Centre & Neurology Department , University and University Hospital of Liège, Liège , Belgium
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17
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Fingelkurts AA, Fingelkurts AA, Bagnato S, Boccagni C, Galardi G. DMN Operational Synchrony Relates to Self-Consciousness: Evidence from Patients in Vegetative and Minimally Conscious States. Open Neuroimag J 2012; 6:55-68. [PMID: 22905075 PMCID: PMC3419863 DOI: 10.2174/1874440001206010055] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 05/19/2012] [Accepted: 06/02/2012] [Indexed: 12/29/2022] Open
Abstract
The default mode network (DMN) has been consistently activated across a wide variety of self-related tasks, leading to a proposal of the DMN’s role in self-related processing. Indeed, there is limited fMRI evidence that the functional connectivity within the DMN may underlie a phenomenon referred to as self-awareness. At the same time, none of the known studies have explicitly investigated neuronal functional interactions among brain areas that comprise the DMN as a function of self-consciousness loss. To fill this gap, EEG operational synchrony analysis [1, 2] was performed in patients with severe brain injuries in vegetative and minimally conscious states to study the strength of DMN operational synchrony as a function of self-consciousness expression. We demonstrated that the strength of DMN EEG operational synchrony was smallest or even absent in patients in vegetative state, intermediate in patients in minimally conscious state and highest in healthy fully self-conscious subjects. At the same time the process of ecoupling of operations performed by neuronal assemblies that comprise the DMN was highest in patients in vegetative state, intermediate in patients in minimally conscious state and minimal in healthy fully self-conscious subjects. The DMN’s frontal EEG operational module had the strongest decrease in operational synchrony strength as a function of selfconsciousness loss, when compared with the DMN’s posterior modules. Based on these results it is suggested that the strength of DMN functional connectivity could mediate the strength of self-consciousness expression. The observed alterations similarly occurred across EEG alpha, beta1 and beta2 frequency oscillations. Presented results suggest that the EEG operational synchrony within DMN may provide an objective and accurate measure for the assessment of signs of self-(un)consciousness in these challenging patient populations. This method therefore, may complement the current diagnostic procedures for patients with severe brain injuries and, hence, the planning of a rational rehabilitation intervention.
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18
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Pain Perception in Disorders of Consciousness: Neuroscience, Clinical Care, and Ethics in Dialogue. NEUROETHICS-NETH 2012. [DOI: 10.1007/s12152-011-9149-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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19
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Fellinger R, Klimesch W, Schnakers C, Perrin F, Freunberger R, Gruber W, Laureys S, Schabus M. Cognitive processes in disorders of consciousness as revealed by EEG time–frequency analyses. Clin Neurophysiol 2011; 122:2177-84. [PMID: 21511524 DOI: 10.1016/j.clinph.2011.03.004] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 02/04/2011] [Accepted: 03/06/2011] [Indexed: 11/19/2022]
Affiliation(s)
- R Fellinger
- Department of Psychology, Laboratory for Sleep and Consciousness Research and Division of Physiological Psychology, University of Salzburg, Hellbrunnerstraße 34, 5020 Salzburg, Austria
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20
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Assessment of consciousness with electrophysiological and neurological imaging techniques. Curr Opin Crit Care 2011; 17:146-51. [PMID: 21206267 DOI: 10.1097/mcc.0b013e328343476d] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW Brain MRI (diffusion tensor imaging and spectroscopy) and functional neuroimaging (PET, functional MRI, EEG and evoked potential studies) are changing our understanding of patients with disorders of consciousness encountered after coma such as the 'vegetative' or minimally conscious states. RECENT FINDINGS Increasing evidence from functional neuroimaging and electrophysiology demonstrates some residual cognitive processing in a subgroup of patients who clinically fail to show any response to commands, leading to the recent proposal of 'unresponsive wakefulness syndrome' as an alternative name for patients previously coined 'vegetative' or 'apallic'. SUMMARY Consciousness can be viewed as the emergent property of the collective behavior of widespread thalamocortical frontoparietal network connectivity. Data from physiological, pharmacological and pathological alterations of consciousness provide evidence in favor of this hypothesis. Increasing our understanding of the neural correlates of consciousness is helping clinicians to do a better job in terms of diagnosis, prognosis and finally treatment and drug development for these severely brain-damaged patients. The current challenge remains to continue translating this research from the bench to the bedside. Only well controlled large multicentric neuroimaging and electrophysiology studies will enable to identify which paraclinical diagnostic or prognostic test is necessary for our routine evidence-based assessment of individuals with disorders of consciousness.
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21
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Bruno MA, Vanhaudenhuyse A, Thibaut A, Moonen G, Laureys S. From unresponsive wakefulness to minimally conscious PLUS and functional locked-in syndromes: recent advances in our understanding of disorders of consciousness. J Neurol 2011; 258:1373-84. [PMID: 21674197 DOI: 10.1007/s00415-011-6114-x] [Citation(s) in RCA: 393] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 05/16/2011] [Accepted: 05/18/2011] [Indexed: 12/14/2022]
Abstract
Functional neuroimaging and electrophysiology studies are changing our understanding of patients with coma and related states. Some severely brain damaged patients may show residual cortical processing in the absence of behavioural signs of consciousness. Given these new findings, the diagnostic errors and their potential effects on treatment as well as concerns regarding the negative associations intrinsic to the term vegetative state, the European Task Force on Disorders of Consciousness has recently proposed the more neutral and descriptive term unresponsive wakefulness syndrome. When vegetative/unresponsive patients show minimal signs of consciousness but are unable to reliably communicate the term minimally responsive or minimally conscious state (MCS) is used. MCS was recently subcategorized based on the complexity of patients' behaviours: MCS+ describes high-level behavioural responses (i.e., command following, intelligible verbalizations or non-functional communication) and MCS- describes low-level behavioural responses (i.e., visual pursuit, localization of noxious stimulation or contingent behaviour such as appropriate smiling or crying to emotional stimuli). Finally, patients who show non-behavioural evidence of consciousness or communication only measurable via para-clinical testing (i.e., functional MRI, positron emission tomography, EEG or evoked potentials) can be considered to be in a functional locked-in syndrome. An improved assessment of brain function in coma and related states is not only changing nosology and medical care but also offers a better-documented diagnosis and prognosis and helps to further identify the neural correlates of human consciousness.
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Affiliation(s)
- Marie-Aurélie Bruno
- Coma Science Group, Neurology Department and Cyclotron Research Centre, University Hospital and University of Liège, Liège, Belgium
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22
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Gosseries O, Vanhaudenhuyse A, Bruno MA, Demertzi A, Schnakers C, Boly MM, Maudoux A, Moonen G, Laureys S. Disorders of Consciousness: Coma, Vegetative and Minimally Conscious States. ACTA ACUST UNITED AC 2011. [DOI: 10.1007/978-3-642-18047-7_2] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Demertzi A, Schnakers C, Soddu A, Bruno MA, Gosseries O, Vanhaudenhuyse A, Laureys S. Neural plasticity lessons from disorders of consciousness. Front Psychol 2011; 1:245. [PMID: 21833298 PMCID: PMC3153849 DOI: 10.3389/fpsyg.2010.00245] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2010] [Accepted: 12/24/2010] [Indexed: 11/20/2022] Open
Abstract
Communication and intentional behavior are supported by the brain's integrity at a structural and a functional level. When widespread loss of cerebral connectivity is brought about as a result of a severe brain injury, in many cases patients are not capable of conscious interactive behavior and are said to suffer from disorders of consciousness (e.g., coma, vegetative state/unresponsive wakefulness syndrome, minimally conscious states). This lesion paradigm has offered not only clinical insights, as how to improve diagnosis, prognosis, and treatment, but also put forward scientific opportunities to study the brain's plastic abilities. We here review interventional and observational studies performed in severely brain-injured patients with regards to recovery of consciousness. The study of the recovered conscious brain (spontaneous and/or after surgical or pharmacologic interventions), suggests a link between some specific brain areas and the capacity of the brain to sustain conscious experience, challenging at the same time the notion of fixed temporal boundaries in rehabilitative processes. Altered functional connectivity, cerebral structural reorganization as well as behavioral amelioration after invasive treatments will be discussed as the main indices for plasticity in these challenging patients. The study of patients with chronic disorders of consciousness may, thus, provide further insights not only at a clinical level (i.e., medical management and rehabilitation) but also from a scientific-theoretical perspective (i.e., the brain's plastic abilities and the pursuit of the neural correlate of consciousness).
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Affiliation(s)
- Athena Demertzi
- Coma Science Group, Cyclotron Research Centre and Neurology Department, Sart Tilman, University and University Hospital of Liège Liège, Belgium
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25
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Ethics in Disorders of Consciousness. ACTA ACUST UNITED AC 2011. [DOI: 10.1007/978-3-642-18081-1_59] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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26
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Demertzi A, Schnakers C, Ledoux D, Chatelle C, Bruno MA, Vanhaudenhuyse A, Boly M, Moonen G, Laureys S. Different beliefs about pain perception in the vegetative and minimally conscious states: a European survey of medical and paramedical professionals. PROGRESS IN BRAIN RESEARCH 2009; 177:329-38. [PMID: 19818911 DOI: 10.1016/s0079-6123(09)17722-1] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Pain management in severely brain-damaged patients constitutes a clinical and ethical stake. At the bedside, assessing the presence of pain and suffering is challenging due to both patients' physical condition and inherent limitations of clinical assessment. Neuroimaging studies support the existence of distinct cerebral responses to noxious stimulation in brain death, vegetative state, and minimally conscious state. We here provide results from a European survey on 2059 medical and paramedical professionals' beliefs on possible pain perception in patients with disorders of consciousness. To the question "Do you think that patients in a vegetative state can feel pain?," 68% of the interviewed paramedical caregivers (n=538) and 56% of medical doctors (n=1166) answered "yes" (no data on exact profession in 17% of total sample). Logistic regression analysis showed that paramedical professionals, religious caregivers, and older caregivers reported more often that vegetative patients may experience pain. Following professional background, religion was the highest predictor of caregivers' opinion: 64% of religious (n=1009; 850 Christians) versus 52% of nonreligious respondents (n=830) answered positively (missing data on religion in 11% of total sample). To the question "Do you think that patients in a minimally conscious state can feel pain?" nearly all interviewed caregivers answered "yes" (96% of the medical doctors and 97% of the paramedical caregivers). Women and religious caregivers reported more often that minimally conscious patients may experience pain. These results are discussed in terms of existing definitions of pain and suffering, the remaining uncertainty on the clinical assessment of pain as a subjective first-person experience and recent functional neuroimaging findings on nociceptive processing in disorders of consciousness. In our view, more research is needed to increase our understanding of residual sensation in vegetative and minimally conscious patients and to propose evidence-based medical guidelines for the management of possible pain perception and suffering in these vulnerable patient populations.
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Affiliation(s)
- A Demertzi
- Coma Science Group, Cyclotron Research Center and Neurology Department, University of Liège, Liège, Belgium
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Abstract
Vegetative state (VS) is a clinical condition in the severely brain damaged, characterized by wakefulness but unaccompanied by any evidence of awareness of self or environment, voluntary or purposeful behavioral responses to external stimuli, and communication. A metabolic dysfunction of the frontal-parietal network is thought to be responsible for the “functional disconnection” underlying it. Most subjects recover with or without residual disabilities depending on the extent of brain damage. However, VS persists for over 1 year in about 15% of all cases, with exceptional later recovery; prolonged observation has thus become possible and our perspectives have expanded substantially. In recent years, brain activation in response to painful or emotional stimuli (e.g., the mother’s voice or presence) or under stimulus conditions implying processing at varying levels of functional complexity (including learning and semantic functions) has been documented in unambiguously diagnosed VS subjects by advanced electrophysiological and neuroimaging techniques. Methods, experimental conditions, and the results of studies published in years 2002–2008 are summarized. The extent to which brain activation concomitant to external events reflect brain function remains to be investigated. Today, VS nevertheless appears neither static nor homogeneous. An updated characterization also taking the evidence of residual brain responsiveness into account is due. Research with advanced technologies and sophisticated paradigms of brain activation in VS may help us to understand the basic neural processes underlying human consciousness.
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Affiliation(s)
- Francesco Riganello
- Semi-intensive Care Unit, S. Anna Institute – RAN (Research in Advanced Neurorehabilitation), Crotone, Italy
| | - Walter G. Sannita
- Department of Motor Science and Rehabilitation, University of Genova, Italy
- Department of Psychiatry, State University of New York, Stony Brook, NY, USA
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